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"Indonesia merupakan salah satu negara yang tercatat sebagai negara ketiga yang mempunyai cadangan Laterit terbesar setelah New Caledonia dan Filipina (PSDMBP, Kementrian ESDM, 2015). Bijih nikel laterit umumnya terbagi menjadi 2 tipe bijih yaitu bijih limonite yang memiliki kandungan Fe besar dan Ni kecil (sekitar 0.8-1.5%) dan bijih saprolit yang memiliki kandungan Fe kecil dan Ni besar (sekitar 1.5-2.5%) (Chen, Shiau, Liu, Hwang, 2016). Untuk meningkatkan nilai tambah bijih nikel, maka perlu dilakukan pengolahan/pemurnian bijih nikel. Penggunaan komposit pelet sebagai material memunculkan gagasan untuk menggunakan bijih besi dengan kadar rendah dalam menghasilkan pig iron (Kawigraha A., et.al. 2013). Selain komposit, proses reduksi memiliki peranan penting dalam pembuatan nikel. Parameter rasio batubara, temperatur proses dan waktu proses dalam proses reduksi, rasio penambahan zat aditif (Na2SO4) (Yongli Li et al., 2012) juga dijadikan sebagai parameter proses reduksi komposit bijih saprolit. Parameter-parameter yang digunakan adalah % rasio batubara, temperatur, durasi waktu dan jenis zat aditif dengan masing-masing 3 level dengan variabel responnya yaitu % mass Ni. Kandungan mineral Ni (% mass Ni) didapatkan dari hasil analisis XRF. Tujuan penelitian ini adalah untuk mendapatkan kombinasi parameter optimal proses reduksi komposit bijih saprolit pada Tube Furnace dan menghitung biaya operasional untuk 1x batch pilot plant pada tungku Tunnel Kiln berdasarkan kombinasi parameter yang paling optimal. Untuk mendapatkan metode optimasi terbaik dari metode RSM, ANN, ANFIS dan SVM serta kombinsi parameter paling optimal berdasarkan nilai MSE terkecil. Nilai MSE metode RSM yaitu 0.007110, metode ANN yaitu 0.004604, metode ANFIS yaitu 0.014625 dan metode SVM yaitu 0.015338. Sehingga metode optimasi terbaik adalah metode ANN. Kombinasi parameter yang paling optimal adalah kombinasi yang memiliki % mass Ni 1.2 dengan % rasio batubara 15, temperatur 1200 0C, durasi tahan 3 jam dan jenis zat aditif Ca2S04 atau komposit SB15Ca10P2 pada temperatur 1200 0C ditahan selama 3 jam.

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Indonesia is one of the largest in the world as the third country that has the largest laterite reserves in the world after New Caledonia and Philippines (PSDMBP, Ministry of Energy and Mineral Resources, 2015). Laterite nickel ore is generally divided into 2 types of ore, namely limonite ore which has large Fe content and small Ni (around 0.8-1.5%) and saprolite ore which has small Fe content and large Ni (around 1.5-2.5%) (Chen, Shiau, Liu, Hwang, 2016). To increase the added value of nickel content, it is necessary to process/refine nickel ore. To use of composite pellets as material raises the idea of using low grade iron ore to produce pig iron (Kawigraha et.al. 2013). In addition to composites, the reduction process, the ratio of addition of additives (Nas2SO4) (Yongli Li et.al, 2012) are also used as parameters for the reduction of saprolite ore composites. The parameter used are % coal ratio, temperature, duration time and type of additive with each 3 level and the response variable is % mass Ni. The content of mineral (% mass Ni) is obtained from the result of XRF analysis. The purposes of this study was to obtain a combination of optimal parameters for the reduction of saprolite ore composites in the Tube Furnace and calculate operational cost for 1x batch pilot plant in Tunnel Kiln furnace based on optimal parameter combination. To get the best optimization method from RSM, ANN, ANFIS and SVM method and optimal parameter combination based on the smallest MSE value. The MSE value of RSM method is 0.007110, ANN method is 0.004604, ANFIS method is 0.014625, and the SVM method is 0.015338. So, the best optimization is ANN method. The most optimal combination of parameter is a combination with % mass Ni 1.2, % coal ratio 15, temperature 1200 0C, duration time 3 hours, and type of additive is Ca2SO4 or composite SB15Ca10P2 with temperature 1200 0C for 3 hours."

"Studi reduksi karbotermik pada bijih nikel saprolit ini bertujuan untuk mengetahui pengaruh temperatur dalam memperoleh kadar nikel yang optimal. Pengujian dilakukan pada empat temperatur yang berbeda, yaitu: 700, 800, 900, dan 1000°C selama 60 menit. Pada proses pembakaran, perbandingan bijih nikel saprolit dan batubara, masing-masing adalah 20 dan 80 gram. Selama proses pembakaran pada temperatur 700-1000°C, mulai terlihat metalisasi besi pada temperatur 900°C, sedangkan metalisasi nikel dan kobalt yang mulai terlihat pada temperatur yang lebih rendah. Metalisasi nikel, kobalt, dan besi dilihat secara kualitatif melalui karakterisasi Difraksi Sinar-X (XRD) dan untuk mengetahui masing-masing kadar unsur yang diperoleh dari proses reduksi karbotermik dengan menggunakan Floresensi Sinar-X (XRF). Berdasarkan studi yang dilakukan, diperoleh kadar nikel yang optimal 8,23% pada temperatur 800°C selama 60 menit.

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The study of carbothermic reduction on saprolitic nickel ore aims to determine the effect of temperature in obtaining optimal levels of nickel recovery. The experiments carried out at four different temperatures, they are 700, 800, 900, and 1000oC for 60 minutes. In the reduction process, the ratio of saprolite ore and coal are 20 and 80 gram, respectively. During the reduction process at temperatures between 700-1000°C, began to look the metallization of iron at a temperature of 900°C, while the metallization of nickel and cobalt are beginning to look at lower temperature. The metallization of nickel, cobalt, and iron quantitively seen through the characterization of X-ray Diffraction (XRD) and to determine the concentration of each element obtained from the carbothermic reduction process using X-ray Flourescent (XRF). Based on studies conducted, the optimal nickel grade of 8.23% is at a temperature of 800°C for 60 minutes."

"Indonesia seharusnya bisa membangun industri besi-baja nasional yang mandiri karena Indonesia memiliki cadangan bijih besi berupa bijih besi primer yang melimpah. Sebelum digunakan sebagai bahan baku pembuatan besi baja, pada bijih besi dilakukan proses reduksi, yaitu proses untuk memisahkan besi yang terkandung dalam bijih besi dari oksigen dan pengotor yang mengikatnya. Salah satu metode reduksi bijih besi adalah reduksi langsung.Pada proses reduksi langsung terdapat beberapa parameter yang mempengaruhi terbentuknya Fe pada produk reduksi langsung, salah satunya adalah temperatur. Temperatur berpengaruh terhadap berlangsungnya proses reduksi oksida besi menjadi Fe. Tujuan dari penelitian ini adalah untuk mengetahui efek temperatur reduksi terhadap perubahan senyawa dan Fe yang terbentuk pada produk reduksi langsung. Proses reduksi dilakukan pada pelet komposit bijih besi/batubara dengan komposisi massa 1:1 dengan menggunakan single conveyor belt hearth furnace dengan variasi temperatur reduksi 500°C, 700°C dan 900°C dengan waktu tahan 25 menit.Hasil penelitian menunjukkan pada temperatur reduksi 500oC hematit yang dikandung pelet komposit tereduksi oleh gas CO hasil devolatilisasi batubara membentuk magnetit namun belum terjadi pembentukan Fe. Dan pada temperatur 700°C hematit telah tereduksi sepenuhnya dan terbentuk Fe yang masih dalam jumlah yang sedikit. Sedangkan pada temperatur 900°C, Fe yang terbentuk semakin banyak namun masih terdapat senyawa magnetit pada produk reduksi langsung.

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Indonesia should be able to build national iron-steel industry independently because Indonesia has abundant reserves of iron ore in the form of primary iron ore. Before being used as raw material in the steel manufacture, iron ore encounter the reduction process, which is a process to separate iron contained in iron ore from the binding of oxygen and impurities. One of iron ore reduction methods is direct reduction.

In the direct reduction process, there are several parameters that affect the formation of Fe in the direct reduction product. One of the parameters is temperature. Temperature effects on the course of the reduction process of iron oxide to form the Fe. The purpose of this study is to determine the effects of temperature reduction on the compound changes and Fe formation in direct reduction product. Reduction process performed on the composite pellets of iron ore / coal with a 1:1 mass composition using a single conveyor belt hearth furnace with reduction temperature variation: 500°C, 700°C and 900°C with holding time of 25 minutes.

The results showed that, in 500°C reduction temperature, hematite compounds contained in composite pellets is reduced by CO gas from coal devolatilization forming magnetite but the formation of Fe has not been happened. And at temperature of 700°C, hematite has been reduced completely and Fe is formed in very small amount. While at temperature of 900°C, Fe formation becomes much more to happen but there is still magnetite compound in direct production product."

"Mineral mangan merupakan salah satu mineral yang paling banyak ditemui di kerak bumi. Sebagian besar produksi mangan dan paduannya di dunia saat ini diserap oleh industri baja. Ferromangan merupakan salah satu logam paduan dengan kandungan mangan yang sangat tinggi, yaitu sekitar 65 - 90%. Sebanyak 90%, ferromangan digunakan untuk menambahkan unsur mangan kedalam material baja untuk memperbaiki sifat-sifat mekanik dari material baja, seperti kekuatan, hardenability, dan ketahanan terhadap aus. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan kadar kokas terhadap keefisienan proses reduksi bijih mangan lokal kadar menengah menjadi produk ferromangan. Proses reduksi dilakukan pada tungku submerged arc furnace tiga fasa dengan kapasitas 100 Kg/Batch dilengkapi dengan tiga buah elektroda grafit. Setiap percobaan menggunakan 30 Kg bijih mangan lokal, 12 Kg limestone, dan kadar kokas yang bervariasi, yaitu 5,5 Kg (18,33%), 7,5 Kg (25,00%), 9,5 Kg (31,67%), dan 11,5 Kg (38,33%). Hasil penelitian menunjukkan bahwa kuantitas dan kualitas produk ferromangan yang dihasilkan meningkat seiring dengan bertambahnya kadar kokas yang digunakan. Dimana kandungan mangan pada ferromangan dan massa/yield produk ferromangan cenderung meningkat. Kandungan mangan pada produk ferromangan tertinggi sebesar 78% pada pengujian menggunakan kokas sebanyak 7,5 Kg (25,00%). Sedangkan massa produk ferromangan tertinggi terdapat pada pengujian dengan menggunakan kokas sebanyak 9,5 Kg (31,67%), yaitu 12,8 Kg. Dan pada penggunaan energi selama proses berlangsung cenderung menurun dengan penambahan kokas, dimana penggunaan energi terendah selama proses reduksi berlangsung pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) sebesar 7,03 KWh/Kg. Namun konsumsi elektroda cenderung meningkat. Sehingga konsumsi elektroda grafit terendah pada saat menggunakan kokas 5,5 Kg (18,33%), yaitu sebesar 0,75 Kg. Berdasarkan aspek ekonomi, pengujian dengan keuntungan tertinggi terdapat pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) yaitu sebesar Rp 62.565 pada tiap satu kali pengujian.

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Manganese is one of the most common minerals in the earth’s crust.Manganese plays an important role in the development of various steel making processes and its continuing importance is indicated by the fact that about 90% of all manganese alloys consumed annually goes into steel production as an alloying element in the form of ferromanganese. Ferromanganese is one of the metal alloys with a high content of manganese, which is about 65 - 90%. Manganese has four functions to steel such as desulphurizing agent, deoxidation agent, enhancing hardness, and wear resistance. This research, studies have been made to obtain the most optimum raw material composition to produce ferromanganese metal based on local medium grade manganese ore with various amount of cokes as its main variable. The process is conducted four times by smelting manganese ore into ferromanganese metal in mini submerged arc furnace (SAF) technology using three graphite electrodes. The process begin with using 30 kg of medium grade manganese ore from Jember, East Jawa-Indonesia, 12 kg of limestone as its fluxing agent, and various number of cokes from 5,5 kg (18,33%), 7,5 kg (25%), 9,5 kg (31,67%), and 11,5 kg (38,33%). Influence of various amount of cokes being used in this study have been investigated. The experiment conducted by increasing number of cokes carried out good results. Higher consumption of cokes will produce bigger number of ferromanganese metal and also the manganese content inside it. The most optimum composition of cokes shown by this study is 9,5 kg (31,67%), producing the biggest number of product at 12,8 kg of ferromanganese and consuming the least energi at 7,03 kwh/kg FeMn. The other result also showed that adding 7,5 kg (25%) of cokes will produce 78% manganese content inside the metal which was the highest manganese content. However, with an increase of cokes, the electrode consumption will also increase. The experiment with 5,5 kg (18,33%) of cokes carried out the least electrodes consumption at 0,75 kg/process. Moreover, to support the optimum raw material composition, economic evaluation has been conducted. The biggest profit is Rp 62.565,-/process for 9,5 kg (31,67%) of cokes.

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Pengolahan bijih nikel menggunakan teknologi peleburan konvensional (blast furnace dan rotary kiln electric furnace) membutuhkan konsumsi energi yang besar serta keekonomisan proses dibatasi hanya untuk bijih nikel kadar tinggi (lebih dari 2% Ni). Proses reduksi selektif merupakan salah satu teknologi alternatif dalam pengolahan bijih nikel laterit (kadar rendah) menjadi konsentrat ferronikel dengan menggunakan temperatur proses (atau konsumsi energi) yang rendah. Namun, rendahnya kadar nikel dan recovery yang dihasilkan masih menjadi permasalahan pada teknologi tersebut. Dalam penelitian ini telah dipelajari mengenai pengaruh basisitas (biner, terner dan kuarterner) dalam proses reduksi selektif bijih nikel laterit (limonit dan saprolit) terhadap (1) kadar dan recovery besi-nikel dalam konsentrat, (2) transformasi fasa, (3) struktur mikro ferronikel yang terbentuk, serta (4) kinetika reaksi reduksi. Proses reduksi bijih nikel laterit dilakukan menggunakan muffle furnace dengan batubara sebagai reduktan dan sodium sulfat sebagai aditif. Dari hasil penelitian diperoleh bahwa besi dan nikel dalam senyawa magnesium silikat-hidroksida (lizardite) dalam bijih nikel saprolit memiliki tingkat reduksibilitas yang lebih rendah dibandingkan dalam bentuk senyawa oksida-hidroksida (goethite) pada bijih nikel limonit. Modifikasi basisitas dengan penambahan CaO, yaitu basisitas biner (CaO/SiO₂) dengan nilai 0,1 merupakan basisitas optimum untuk bijih nikel limonit (menghasilkan konsentrat dengan kadar dan recovery nikel sebesar 6,14% dan 89,94%), sedangkan basisitas terner (CaO+MgO/SiO₂) dengan nilai 0,6 untuk bijih nikel saprolit (menghasilkan konsentrat dengan kadar dan recovery nikel sebesar 16,11% dan 50,57%). Penambahan CaO mampu memecah ikatan besi dan nikel dalam senyawa silikat, dimana penambahan dalam jumlah yang optimal memberikan dampak positif terhadap peningkatan kadar dan recovery nikel. Modifikasi basisitas melalui penambahan SiO₂ menyebabkan terbentuknya senyawa besi silikat, yang akan menghambat laju reduksi besi oksida, namun efektivitasnya jauh lebih rendah dibandingkan besi sulfida dikarenakan titik leburnya yang tinggi. Penambahan MgO akan menyebabkan semakin banyaknya senyawa forsterite (magnesium silikat) dan diopside yang terbentuk, dimana keduanya juga memiliki titik lebur yang lebih tinggi dibandingkan troilite. Penambahan Al₂O₃ akan menyebabkan terbentuknya senyawa alumino-magnesioferrite dengan tingkat reduksibilitas yang rendah. 

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Nickel laterite processing by using conventional technology (blast furnace and rotary kiln electric furnace) requires a large amount of energy consumption. Its feasibility is limited to high-grade ores (more than 2% Ni). The selective reduction process is an alternative technology in low-grade nickel ores processing using low temperature (or low energy consumption). Nevertheless, the low nickel grade and recovery of the product are still the main problems in the selective reduction process. In this work, the effect of basicity (binary, ternary and quarternary) in selective reduction of lateritic nickel ore (limonite and saprolite) on (1) grade and recovery of iron-nickel in concentrate; (2) phase transformation; (3) microstructure of ferronickel; and (4) kinetic of reduction has been investigated clearly. The reduction process of nickel laterite was carried out in a muffle furnace with coal and sodium sulfate as reductant and additive, respectively. The result showed that iron and nickel in silicate magnesium-hydroxide (lizardite) in saprolite had lower reducibility than oxide-hydroxide (goethite) in limonite. Modifying the basicity with CaO addition, which was 0.1 of binary basicity (CaO/SiO₂), was the optimum basicity for limonite (producing concentrate with nickel grade and recovery of 6.14% and 89.94%, respectively), while the 0.6 of ternary basicity (CaO+MgO/SiO₂) for saprolite (producing concentrate with nickel grade and recovery of 16.11% and 50.57%, respectively). The CaO addition could break the iron-nickel bond in silicate magnesium. Its addition in optimal amount had positively affected the increase of nickel grade and recovery. Modifying basicity with SiO₂ addition caused the formation of iron silicate, which could inhibit the reduction of iron oxide. However, it has lower effectivity than iron sulfide due to its high melting point temperature. The MgO addition would promote the formation of forsterite (magnesium silicate) and diopside, which also has high melting point than troilite. The addition of Al₂O₃ would generate the alumino-magnesioferrite, which had low reducibility.

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"Dalam pengolahannya, proses reduksi bijih besi secara umum terbagi atas dua metode yaitu reduksi langsung (direct reduction) dan reduksi tidak langsung (indirect reduction). Indirect reduction dilakukan dalam blast furnace dengan reduktor berupa kokas atau char dengan temperatur di atas titik lebur besi dengan produk berupa lelehan logam Fe. Sedangkan proses reduksi langsung adalah proses reduksi dengan menghindari fasa cair dan menggunakan batubara atau minyak bumi sebagai reduktornya dan membutuhkan feed bijih besi dengan kadar Fe yang tinggi seperti yang dimiliki bijih besi di Indonesia.Dalam penelitian ini, proses reduksi langsung yang menggunakan pelet komposit bijih besi/batubara dilakukan dengan menggunakan teknologi single conveyor belt hearth furnace. Pelet yang digunakan pada penelitian ini berasal dari Kalimantan Selatan, Indonesia. Sampel merupakan mineral besi jenis lump ore dengan ukuran partikel -140#. Reduktor yang digunakan adalah batubara yang memiliki calorific value tertentu dan sebagai pengikat (binder) butir-butir campuran bijih besi/batubara pada proses peletasi digunakan bentonit 1% yang memiliki nilai plastisitas tertentu. Komposisi (mass ratio) dari pelet komposit tentunya mempengaruhi perolehan besi yang dihasilkan, karena penentuan mass ratio dari pelet komposit menentukan jumlah reduktor yang digunakan. Mass ratio pelet yang paling efisien dapat menentukan perolehan fasa Fe yang diperoleh, sehingga kita dapat menentukan mass ratio yang menghasilkan Fe paling banyak, dalam skala laboratorium.Tujuan penelitian yaitu untuk mengetahui pengaruh mass ratio pelet sehingga dapat diperoleh mass ratio yang paling efisien pada proses reduksi langsung dengan teknologi single conveyor belt hearth furnace. Variasi yang dilakukan ialah melakukan reduksi langsung dengan mass ratio pelet komposit bijih besi : batu bara 2:1, 1:1 dan 1:2. Hasil penelitian menunjukkan terjadinya perbedaan reaksi yang mempengaruhi fasa yang dihasilkan sesuai dengan fungsi waktu prosesnya.

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The treatment process requires the separation of iron from iron ore with impurities-impurities. This process is called the iron ore reduction process. In processing, iron ore reduction process is generally divided into two methods: direct reduction (direct reduction) and reduction (indirect reduction). Indirect reduction is done in a blast furnace with a reducing agent such as coke or char at temperatures above the melting point of the product in the form of molten iron to Fe metal. While the direct reduction process is the reduction process by avoiding the liquid phase and the use of coal or oil as needed feed reduktornya and iron ore with high Fe levels like those of iron ore in Indonesia.

In this study, the direct reduction process using composite pellets of iron ore / coal performed using a single technology conveyor belt furnace hearth. Pellets used in this study came from South Kalimantan, Indonesia. The sample is a mineral type of lump iron ore with a particle size of -140 #. Reducing agent used is coal that has a certain calorific value and the binder (binder) mixed grains of iron ore / coal used in the process pelletasi 1% bentonite which has a certain plasticity. Composition (mass ratio) of composite pellets of course affect the acquisition of iron is produced, because the determination of the mass ratio of the composite pellets were used to determine the amount of reducing agent. Mass ratio pellets to determine the most efficient acquisition of Fe phase obtained, so that we can determine the mass ratio that produces Fe at most, on a laboratory scale.

The purpose of research is to determine the effect of pellet mass ratio that can be obtained in the most efficient mass ratio in the direct reduction technology with a single conveyor belt furnace hearth. Variations that we used is mass reduction ratio composite iron ore pellets: coal 2:1, 1:1 and 1:2. The results showed the reaction that affects the phase difference is generated according to the function of the process time."

"Sources nickel laterite deposit of the world are mostly found in the tropic such as Indonesia. The initial composition of nickel saprolite ore is characterized by XRF. Saprolte ore was reduced use coal 15% wt at 1000°C for 60 minutes. The result of reduction is characterized by XRD. Effect of roasting reduction to recovery nickel also affect the result leaching use solvent sulphuric acid (H2SO4) for 240 minutes at 100°C with varying concentrations of 0.5 M, 1 M, and 2 M. The content of nickel dissolved in pregnant leach solution calculated using Atomic Absorbance Spectroscopy (AAS).Result of XRD characterization shows phase transformation into Fe3O4, NiO, and FeNi after reduction roasting. Sulphuric Acid at concentration 1 Molar has the highest nickel recovery with 52.75% in reduced saprolite ore."

"Proses reduksi bijih besi adalah proses pemisahan besi yang terkandung dalam bijih besi dari oksigen dan pengotornya. Pada umumnya proses reduksi bijih besi terbagi menjadi dua metode yaitu reduksi tidak langsung dan reduksi langsung. Proses reduksi bijih besi secara tidak langsung dilakukan dalam blast furnace dengan reduktor berupa kokas atau char dengan temperatur di atas titik lebur besi dengan produk berupa lelehan logam Fe. Sedangkan proses reduksi langsung adalah proses reduksi dengan menghindari fasa cair dan menggunakan batubara atau minyak bumi sebagai reduktornya dan membutuhkan feed bijih besi dengan kadar Fe yang tinggi seperti yang dimiliki bijih besi di Indonesia.Pada penelitian ini proses reduksi langsung pelet komposit bijih besi/batu bara dilakukan dengan menggunakan teknologi single conveyor belt hearth furnace dan menggunakan pelet yang berasal dari Kalimantan Selatan, Indonesia. Sampel merupakan mineral besi jenis lump ore dengan ukuran partikel -140#. Batubara digunakan sebagai reduktor yang memiliki calorific value tertentu dan bentonit digunakan sebagai pengikat butir-butir campuran bijih besi/batu bara pada proses peletasi. Waktu tahan memegang peranan penting dalam proses reduksi pelet komposit karena menentukan banyaknya CO yang bereaksi dan berpengaruh terhadap fasa Fe yang berhasil diperoleh.Tujuan penelitian adalah mengetahui pengaruh perbedaan waktu tahan reduksi pelet komposit bijih besi/batu bara terhadap pembentukan Fe dengan teknologi single conveyor belt hearth furnace. Variasi yang dilakukan ialah melakukan reduksi langsung dengan waktu tahan reduksi 15, 20, 25 dan 30 menit. Hasil penelitian menunjukkan terjadinya perbedaan reaksi yang mempengaruhi fasa sesuai dengan fungsi waktu prosesnya.

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Iron ore reduction process is the process of separating iron contained in iron ore of oxygen and impurities. In general, the iron ore reduction process is divided into two methods, indirect reduction and direct reduction. Indirect reduction process occurs in a blast furnace with a reducing agent such as coke or char at temperatures above the melting point and the product transform from molten metal to Fe metal. While the direct reduction process is a process by avoiding the liquid phase and the use of coal or oil as a reductant and iron ore with high Fe levels like those of iron ore in Indonesia.

In this research, the process of direct reduction composite pellets of iron ore / coal using a technology single conveyor belt hearth furnace. Pellets used in this study came from South Kalimantan, Indonesia. The sample is a mineral type of lump iron ore with a particle size of -140 #. Coal is used as a reductant that has a certain calorific value and bentonite is used as a binder mixed grains of iron ore / coal used in the pelletizing process. Residence time plays an important role in the reduction process because residence time determines the amount of CO react in the process reduction of composite pellets and effect on the Fe-phase was successfully obtained.

The research objective was to determine the effect of different residence time reduction of composite pellets of iron ore / coal Fe formation with technology single conveyor belt hearth furnace. Variation in this research is a direct reduction with residence time reduction 15, 20, 25 and 30 minutes. The results showed the difference of phase that affect the process in accordance with a function of time."

"[Kurangnya penguasaan teknologi pengolahan bijih mangan menjadi ferromangan merupakan salah satu penyebab tingginya impor ferromangan yang dilakukan oleh industri baja nasional. Kualitas produk ferromangan dan juga pencapaian konsumsi energi listrik yang effisien per Kg ferromangan yang dihasilkan menjadi faktor penting pengembangan teknologi ini. Jumlah batubara sebagai reduktor merupakan salah satu parameter utama kesuksesan produksi yang nantinya akan dilihat berdasarkan kualitas FeMn (Kadar Mn hingga 75%) dan seberapa besar power consumption-nya. Pada penelitian ini akan dilakukan proses pembuatan ferromangan dari bahan baku bijih mangan local dengan menggunakan SAF (Submerged Arc Furnace). Variabel yang akan dipakai adalah jumlah batubara sebagai reduktor, yaitu 40.33%, 47%, 53.67%, dan 60.33%. Karakterisasi produk menggunakan XRF (input dan ouput produk), XRD (Mn Ore), dan Proksimat analisis (batubara).Hasil penelitian menunjukan dengan kenaikan jumlah reduktor maka massa produk, kadar mangan, yield product, massa off gas, konsumsi energi, dan persentase fosfor dan sulfur akan meningkat pula. Jumlah produk ferromangan tertinggi didapat pada angka 9.1 kg dengan menggunakan batubara 53.67%. kadar Mn tertinggi didapat pada angka 72% dengan pemakaian batubara 53.67% dan kadar terkecil yaitu 63.12% dengan pemakaian batubara 40.33%. Off gass tertinggi pada angka 33.5 kg dengan pemakaian batubara 60.33% menunjukkan proses reduksi yang tidak optimal, dimana proses reduksi tidak berjalan sempurna. Energi yang paling tinggi di dapatkan pada berat batubara 40.33% yaitu 12.45 Kwh/Kg FeMn, sedangkan yang paling optimum dari segi energi, yaitu didapatkan pada berat batubara 47% dengan 7.56 Kwh/Kg FeMn. %P yang paling tinggi dengan pemakaian batubara 53.67% dengan hasil 0.74% fosfor. Sedangkan untuk %S yang paling tinggi dengan pemakaian batubara 16.1 Kg dengan hasil 0.9% sulfur. Batubara dengan persentase 47% merupakan yang paling optimum apabila dilihat dari aspek ekonomi, %P %S, konsumsi energi, dan kadar mangan.;Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java ? Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal.;Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java ? Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal., Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java – Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal.]"

"Disertasi ini membahas pengaruh batubara pada bijih besi tipe lateritik dalam bentuk pelet komposit. Tiga sampel R, C dan CTR digunakan dalam penelitian ini. R merupakan sampel yang berasal dari lokasi tambang, C merupakan bijih besi R yang telah dicuci dengan classifyer, dan CTR merupakan sampel C yang telah dilewatkan pada pemisah magnetik. Ketiganya berbeda dalam jumlah goethit, hematit dan magnetit. Sampel C hanya digunakan untuk reduksi diatas 1000 °C. Batubara yang digunakan sebagai reduktor merupakan batubara dengan kadar karbon rendah. Ketiga sampel digunakan berukuran lebih kecil dari 140 mesh. Sampel ditambahkan batubara dengan jumlah yang bervariasi, dibuat pelet dan dikeringkan. Pelet komposit kemudian direduksi. Reduksi diatas 1000 °C dilakukan dengan tungku tabung. Kecepatan pemanasan tungku 10 °C/menit hingga temperatur yang diinginkan, temperatur ditahan selama 10 menit dan kemudian diturunkan hingga temperatur kamar. Variasi jumlah batubara adalah 20 % berat dan 29 % untuk R dan C serta 31 % untuk CTR. Jumlah batubara yang terakhir tersebut berhubungan dengan komposisi stoekiometri Fet dan C. Variasi temperatur adalah 1100 °C, 1200 °C, 1300 °C dan 1350 °C. Analisis dilakukan dengan XRD untuk mengetahui fasa-fasa yang terbentuk dan diikuti dengan kuantifikasi fasa dengan metode Rietvield. Densitas pelet diukur untuk mengetahui perubahannya terhadap perubahan fasa. Mikrostruktur pelet diamati dengan SEM untuk mengetahui perbedaan dari pelet R dan CTR. Reduksi dibawah 1000 °C dilakukan dengan alat Simultaneous Thermal Analysis dan tungku tabung. Reduksi dengan alat STA dilakukan dengan kecepatan 10.

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The dissertation discusses the reduction process of lateritic iron ore-coal composite pellet. Three samples have been used, called R, C and CTR. R is lateritic iron ore from mining, C is washed lateritic iron ore and CTR is lateritic iron ore which has been washed folllowed by magnetic separation. The three samples have different quantity of goethite, hematite and magnetite phases. C has been used only for direct reduction above 1000 °C. The used coal has low fixed carbon. The R, C and CTR are smaller than 140 mesh. The composite pellets are made of mixture of coal and ore.

Reduction above 1000 °C is carried out in tube furnace. Heating rate is 10 °C/minute. The temperature is fixed and maintained for 10 minutes. Then, temperature is decreased by turning off the electricity to room temperature. The composite of R and C are made of 20 % and 29 % of total weight whereas the composite of CTR are made of 20 % and 31 % of total weight. The temperatures are fixed at 1100 °C, 1200 °C, 1300 °C and 1350 °C.

X-Ray Diffraction is used for analysing the phases present after heating and followed by quantification using Rietveld Method. Density of composite pellet are measured. Microstructure of pellets are also investigated using SEM. Reduction below 1000 °C is carried out using Simoultaneous Thermal Analysis and tube furnace. Heating rate is 10 °C/minute. Nitrogen is flowed 20 mL/minute. Obtained thermal graphs are analysed. Reduced samples are analysed using X-Ray Diffraction. During reduction, released gases are analysed using gas analyser."